About Hearing
How does hearing work?
Hearing is a remarkable process. Your ears and your brain work together, in a fraction of a second, so that you can hear the world around you.
How we hear, step by step
Everything we hear starts as a sound wave. Each part of the ear has its own job in turning that wave into a signal the brain can understand.
Step 1
The outer ear
Sound waves are vibrations in the air. The outer ear, the part you can see, collects them and channels them down the ear canal to the eardrum, which starts to vibrate.
When something goes wrong here
Ear wax, an infection or a narrow or closed ear canal can stop sound before it reaches the eardrum. This causes conductive hearing loss.
Step 2
The middle ear
The vibrating eardrum moves the ossicles, three tiny bones in the air-filled middle ear. They pass the vibrations on to the inner ear.
When something goes wrong here
Fluid, an infection or damage to the eardrum or the tiny bones can stop the vibrations reaching the inner ear. This is also conductive hearing loss.
Step 3
The inner ear
In the cochlea, a snail-shaped organ filled with fluid, the vibrations push against tiny hair cells. The hair cells turn the vibrations into electrical nerve impulses.
When something goes wrong here
When hair cells are damaged or missing, for example through ageing, loud noise, genetics or illness, the result is sensorineural hearing loss.
Step 4
The hearing nerve
The auditory nerve connects the cochlea to the hearing centres of the brain. When the impulses reach the brain, they are recognised as sound: a voice, music or a car horn.
When something goes wrong here
If the nerve itself is damaged or missing, the signals cannot reach the brain. This is neural hearing loss.
It all happens in an instant
Your ears never switch off. Because every step happens so quickly, you hear sounds the moment they happen. If any part of this chain does not work as it should, hearing loss can result.
Two ears, one picture of sound
Hearing with both ears lets the brain work out where sounds come from and pick out speech from background noise. That is why hearing loss in one ear can make noisy places so tiring. Hearing loss in one ear
Where hearing loss starts
The part of the ear that is affected decides the type of hearing loss, and the type guides the treatment.
| Part of the ear | What can go wrong | Type of hearing loss |
|---|---|---|
| Outer ear and ear canal | Wax, infection, a narrow or closed ear canal | Conductive |
| Middle ear | Fluid, infection, damage to the eardrum or the tiny bones | Conductive |
| Inner ear (cochlea) | Damaged or missing hair cells | Sensorineural |
| Inner ear and outer or middle ear | Problems in both places at once | Mixed |
| Hearing nerve | A damaged or missing nerve | Neural |
Want to know how well you hear?
A hearing test shows how your hearing is working and what may help.